I don't think they get used to the noise maker.
Previous employer used them to great success. Too bad they only used them in a few areas instead of every opening
2003 gmc 1500hd quadrasteer "Miley"
2000 jeep cherokee "Herman"
194X CJ2a "To be named"
1977 Ranger 150a bass boat
1987 Yamaha Moto 4 quad